USPS API problems?

Don't know if this has to do with API or zen cart (both I am clueless about).

I have set up a test product and other products in zen cart. When I go to my site https://www.contagioushair.com to test shipping, this is what I get when I click on estimate:

test product weight is 1 in zen but shows up 4lbs in usps est. shipping
other products weight is 0.4 in zen but shows up 3.41 lbs in usps est. shipping

I don't understand why. In zen the package tare for small to medium is set to 0:3 and large is set to 0:0 (I don't understand what this is either)

Another thing is that I will only be using usps priority mail, express mail, and global express. My items for now won't weigh much because it is hair extensions (under 1lb).

Why do I get $6.65 for priority mail and $27.60 for express from georgia to kentucky? When we all know priority mail flat rate only costs $4.60, I'm not even going to get into express rate.

I would love to go live for 2008

admin -> configuration -> shipping set your tare weight,

this is added to show you HOW to add weight for packaging

FAQ: https://www.zen-cart.com/tutorials/index.php?article=85

Excuse me for being totally lost but I still don't get it. I will be shipping all packages via usps, mainly the flat rate boxes & envelopes. So I guess my question is

1. What should I set my tare weight too when I don't even understand what it is or how it's calculated (I have read the tutorial and I have the zencart ebook and still clueless)

My product is hair extensions that comes pre-packaged and weighs 4ounces total. So all I do is put it in usps flat rate priority mail box. I don't ship large packages.

So am I too weigh the flat rate box and use that as my tare weight? and for "help now" sake lets say that the box weighs 5 ounces, given my product weighs 4oz, how would that be entered into admin?

Sorry guys but I have searched and searched for this info.

TIA

Well I think I fixed it, I just entered 0:0 and now my weights show up correctly in usps. But this could pose a problem if and when I expand my services so if you guys don't mind still letting me know the above, that would be great.

Yes weigh your box and then use it for the tare weight,
remember that its al set in Lbs so 8 Ozs would be .5 and so on

you can also set the tare for a large box, thats just below,